Azure DocumentDB – General Availability of Service-Managed Failovers

We are excited to announce the general availability of service-managed failovers in Azure DocumentDB, eliminating the need for human intervention to recover from a regional outage.

Running a production database means planning for the unlikely. Regional outages are rare, but when they happen, every second lost can have significant business impact. Previously, protecting against a region-wide failure in Azure DocumentDB required user-initiated actions – starting with monitoring availability and then making a judgment call based on the criticality of the application. Eventually culminating in manually promoting a globally distributed replica cluster as the new primary.

That changes today. Service-Managed Failover is now generally available in Azure DocumentDB.

With this feature enabled, Azure DocumentDB monitors the health of your primary region continuously and when a regional outage is confirmed, the service automatically promotes your replica cluster. 

How It Works

Azure DocumentDB’s cross-region replication lets you maintain a replica cluster in a secondary Azure region. Your primary cluster in Region A handles all reads and writes, while the replica in Region B stays in sync asynchronously and can serve read traffic.

With Service-Managed Failover, the service takes on the role of watching your primary region’s health. If it determines the primary region is unavailable and local recovery across zones isn’t possible it automatically triggers the promotion of the replica cluster. The global read-write connection string is updated under the covers to point to the newly promoted cluster, so your application continues writing without any changes.

Under the hood, this behaves like a forced promotion – because the primary is unreachable, the replication queue can’t be fully drained before the switch. Writes that were committed on the primary but not yet replicated at the time of the outage may not be present on the new primary. In exchange, you get automatic, fast recovery with no human in the loop.

Choosing the Right Failover Mode

Service-Managed Failover is one of three ways a replica cluster can take over the role of the primary.

Understanding the tradeoffs helps you choose the right posture for your workload.

If your workload requires zero data loss, graceful promotion, which drains the replication queue before switching remains the right choice for planned regional failovers.

However, for regional outages where speed of recovery matters more than the risk of losing a very small number of un-replicated writes, Service-Managed Failover gives you hands-free protection.

What You Need to Enable It

Service-Managed Failover is an opt-in setting on the primary cluster, which is disabled by default. To take advantage of it:

1. Ensure you have cross-region replication configured with a replica cluster in a secondary region.
2. Enable the Service-Managed Failover setting on your primary cluster via a support ticket (Portal enablement coming soon).
3. Use the global read-write connection string in your application, which gets automatically updated during a regional failover.

No other application changes are required.

In-Region HA and Cross-Region DR: Better Together

Service-Managed Failover addresses region-wide outages, but it complements rather than replaces in-region high availability (HA). HA protects against shard failures within a region by maintaining a synchronous standby shard – with automatic failover and zero data loss. Enabling both gives you layered protection:

• HA handles node-level failures within your primary region automatically, with no data loss.
• Service-Managed Failover handles region-wide failures automatically, with minimal data loss.

For production workloads, running both is the recommended configuration.

Getting Started

Service-Managed Failover isavailable across Azure regions that support Azure DocumentDB. To get started:

• Learn about failover modes, the benefits they provide and the differences between each mode

About Azure DocumentDB 

Azure DocumentDB is a fully managed document database service for building and modernizing MongoDB-compatible applications. Powered by the open-source DocumentDB engine, it combines familiar APIs, tools, and workflows with Azure’s security, scalability, and operational simplicity. Whether you’re developing new applications or migrating existing MongoDB workloads, Azure DocumentDB helps you get started quickly and scale with confidence.